Baylor College of Medicine (Baylor) is applying for a Clinical Trials Unit (CTU) in response to NIH RFA-AI-05-002 Units for HIV/AIDS Clinical Trials Networks. Baylor (presently Pediatric AIDS Clinical Trials Group [PACTG], Clinical Site 3801) was ranked by the International Maternal, Pediatric, and Adolescent AIDS Clinical Trials (IMPAACT) Network Leadership Group (J. Brooks Jackson, MD, MBA, Principal Investigator [PI], the merged new group of the PACTG, and the perinatal component of the HIV Prevention Trials Network as a "Highly Preferred" Clinical Trials Unit. Factors included in the IMPAACT selection included: 1) demonstrated ability to enroll and retain suitable populations in clinical trials, 2) contributions by site investigators to PACTG committee and protocol/implementation activities, and 3) evidence of a productive publication record by the site's investigators. The Baylor IMPAACT CTU will have two resources of patients: 1) Texas Children's Hospital (TCH) research home of the Section of Allergy and Immunology, Department of Pediatrics, Baylor College of Medicine (Principal Investigator, William T. Shearer, MD, PhD, Section Chief;and the Section of Retrovirology, Department of Pediatrics, Baylor College of Medicine (Site Co-Leader, Mark W. Kline, MD, Section Chief);and 2) Thomas Street Clinic (TSC), Department of Medicine, Baylor College of Medicine (Site leader, Thomas P. Giordano, MD, MPH, Medical Director).With these combined number of patients, the Baylor will have 280, mostly adolescents. HIV-infected patients available for entry into IMPAACT clinical trials designed for 4 high priority areas of focus: 1) Prevention of mother-to-child HIV transmission, 2) Translational Research and Drug Development, 3) Optimization of Clinical Management, including co-morbidities, and 4) Vaccines for Prevention of sexual HIV transmission. Because of its ability to network with over 10 NIH, CDC, and private sources of transitional AIDS research, and its contribution to advancing the understanding of prevention and treatment regimens and pathogenesis, Baylor will be able to make a strong contribution to the NIH HIV/AIDS Clinical Trials Network, particularly protocols targeted to the rapidly expanding HIV-infected adolescent population. ADMINISTRATIVE COMPONENT: